KR20000001579A - Separation and recovery of nickel, vanadium, and molybdenum from waste catalyst of vacuum residue desulfurization - Google Patents

Abstract

PURPOSE: Nickel, vanadium, and molybdenum are separated and recovered individually and continuously, i.e., nickel components by the form of NiSO4 in the solution of oxidation-roasting vacuum residue desulfurization in low temperature and in the solution of precipitating ammonium sulfate; vanadium components by the form of V2O5 from its residual in high temperature; and molybdenum components by the form of CaMoO4. CONSTITUTION: Nickel components which contain in the valuable metals containing in the waste catalysts of the vacuum residue desulfurization are separated and recovered by the form of NiSO4 through the procedure of oxidation-roasting in low temperature, precipitation of ammonium sulfate, and solvent extract, and then crystallization; vanadium and molybdenum components which have in the residue after recovering nickel are separated and recovered by each forms of V2O5 and CaMoO4. through the procedure of soda-roasting in high temperature, the precipitation in water, the selective precipitation, and the calcination.

Description

Separation and Recovery of Nickel, Vanadium, and Molybdenum from Petroleum Desulfurization Waste Catalyst

The present invention is to separate and recover the nickel component of the valuable metal contained in the petroleum desulfurization waste catalyst through low-temperature roasting, ammonium sulfate leaching, solvent extraction and crystallization process, and then the vanadium and molybdenum components contained in the spent catalyst residue after the nickel recovery. NiSO ₄ is effectively recovered and separated by high temperature soda roasting, water leaching, selective precipitation and calcination process, and V ₂ O ₅ and CaMoO ₄ can be used as additives in the production of ferrovanadium and feromolybdenum. The present invention relates to a method for separating and recovering nickel, vanadium and molybdenum from petrochemical waste catalysts that can maximize industrial applicability.

In general, vanadium and molybdenum components of valuable metals in petroleum desulfurization waste catalysts are subjected to direct high temperature soda roasting without low temperature roasting, followed by water leaching, selective precipitation and calcination, and then V ₂ O ₅ and CaMoO ₄ or H ₂ MoO. _It recovers in ₄ forms, and insoluble nickel component is left in the residue and sent to a nickel smelting plant or discarded. For example, the US AMAX Co. recovers molybdenum as MoS ₃ , Vanadium as V ₂ O ₅ , and pressurizes the primary leach residue from the solution of high temperature soda after petrochemical desulfurization waste catalyst. The alumina component was made of Al (OH) ₃ by the reaction in the steam cooker, and the remaining residue contained nickel component. Therefore, the process is sent to the nickel smelter for reprocessing.

Japan's Taiyoukoukou Co. and Taiwan's Full-Yield Co. use a process of separating and recovering only vanadium and molybdenum components by the method described above, and then forming nickel in the residue into a nickel concentrate form.

In addition, CCIT Co. of Japan oxidizes waste catalyst, dissolves the entire roasted product with sulfuric acid, and separates and purifies all components contained in the solution by multi-step solvent extraction. However, the conventional treatment methods described above are not only able to recover nickel directly, but also have problems in terms of low purity and economical efficiency of the secondaryly recovered nickel compound.

The present invention has been researched and developed to effectively recover nickel even from the method of separating and recovering only vanadium and molybdenum by the conventional high temperature soda roasting method as described above.

In particular, the present invention is a low-temperature oxidation of the waste catalyst (Vacuum Residue Desulfurization, VRDS), selective ammonium sulfate leaching of nickel components, solvent extraction and crystallization process by LIX84 to produce high-purity NiSO ₄ and waste catalyst residue after nickel recovery It is an object of the present invention to provide a method for preparing V ₂ O ₅ and CaMoO ₄ compounds with a higher purity than conventional methods.

In order to achieve the above object, in the present invention, by oxidizing the petroleum desulfurization waste catalyst at low temperature, the nickel component is effectively leached by inhibiting the production of insoluble nickel aluminate (NiAl ₂ O ₄ ) compound produced during high temperature soda roasting, and then nickel It is to provide a method for producing nickel sulfate through a separation and recovery process from the leaching solution.

In addition, the waste catalyst residue after the recovery of the sulfur removed nickel is calcined again at high temperature so as to separate and recover the vanadium and molybdenum components, which is a side effect of producing V ₂ O ₅ and CaMoO ₄ with much higher purity than the conventional method. The present invention also provides a separation method.

1 is a process chart of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

That is, in the present invention, the petroleum desulfurization waste catalyst was pulverized with a rod mill to make a particle size of 200 mesh or less, and the water and sulfur components contained in the waste catalyst were removed through low temperature roasting at 350 ° C. .

The waste catalyst obtained by roasting at low temperature was leached into the nickel component with ammonium sulfate, and the nickel component in the leachate was extracted with an organic solvent LIX84 and recovered in the form of nickel sulfate. The vanadium and molybdenum components in the spent catalyst residue from which nickel was extracted were subjected to soda roasting at 900 ° C, water leaching at 80 ° C, ammonium vanadate (NH ₄ VO ₃ ) precipitation by ammonium chloride addition, and calcium molybdate by addition of calcium chloride. It was isolated and recovered by date (CaMoO ₄ ) precipitation method.

As the sodium salt used in the soda roasting is Na ₂ SO were ₄ or leaching effect is to use a good Na ₂ CO ₃ than NaOH, the nickel is recovered spent catalyst is Na ₂ CO ₃ and then mixing the Na ₂ CO ₃ Melting point Na ₂ CO ₃ was reacted with vanadium and molybdenum in the spent catalyst as shown in formulas (1) and (2) by heating to above 850 ° C. to produce water-soluble NaVO ₃ and Na ₂ MoO ₄ .

V ₂ O ₅ (S) + Na ₂ CO ₃ (l) = 2 NaVO ₃ (S) + CO ₂ (g) ------ (1)

MoO ₃ (S) + Na ₂ CO ₃ (l) = Na ₂ MoO ₄ (S) + CO ₂ (g) ------ (2)

NaVO ₃ and Na ₂ MoO ₄ produced as in Formulas (1) and (2) were extracted by water leaching.

Vanadium in the leaching filtrate was recovered by precipitation with NH ₄ VO ₃ precipitate by reacting with ammonia as shown in the following equation (3). The molybdenum component present in the filtrate from which the vanadium was recovered was recovered by calcium molybdate (CaMoO ₄ ) by adding CaCl ₂ as in Formula (4).

_{^{Na + + VO 3 - + NH}} 4 Cl = NH 4 VO 3 + Na + + Cl - ------ (3)

_{^{2Na + + MoO 4 -2 + CaCl}} 2 = CaMoO 4 + 2Na + + 2Cl - ------ (4)

NiSO ₄ separated and recovered by this process is used for nickel plating, and V ₂ O ₅ and CaMoO ₄ obtained by calcining NH ₄ VO ₃ at 500 ° C. are ferrovanadium (FeV) and feromolybdenum (FeMo), which are alloy steel addition materials. It is useful for the preparation of

The following shows a number of experimental examples and preparations made to further refine the present invention as described above, whereby the present invention will be described in detail.

(1) Experimental example of low temperature roasting for petroleum desulfurization waste catalyst

In order to effectively recover valuable metals from spent catalysts, carbon and sulfur components must be removed by oxidation. The higher the roasting temperature, the higher the removal rate of carbon and sulfur components, but at high temperature NiO reacts with Al ₂ O ₃ to form insoluble NiAl ₂ O ₄ compound with spinel structure, which leaches nickel under high and high temperature leaching conditions. This is known to be difficult. Accordingly, in the present invention, a low temperature roasting experiment was performed to leach nickel under the condition that the NiAl ₂ O ₃ compound was not produced.

Low temperature roasting experiment was carried out for 1 hour in a crushed -200mesh waste catalyst sample at 300-500 ℃ temperature while feeding 45g per minute in an electric heating rotary kiln (rotary kiln). At this time, the rotation speed of the rotary roaster was 4 rpm, and the inclination angle was 1.5 degrees.

Table 1 below shows the chemical composition of the petroleum desulfurization waste catalyst as a sample.

Chemical Composition of Petroleum Desulfurization Waste Catalyst as Sample ingredient C S V Mo Ni Al content(%) 5.0 14.1 18.6 1.36 4.74 25.4

As shown in Table 1, the spent catalyst contains a large amount of sulfur and carbon components to be removed, and also contains a large amount of valuable metals such as vanadium and nickel.

Table 2 below shows the chemical composition of the products subjected to low temperature oxidation roasting while changing the temperature of the sample waste catalyst in a rotary roaster.

Changes in Contents with Temperature Changes of Low Temperature Oxidized Waste Catalyst (Unit:%) Elemental component ＼ roasting temperature C S V Mo Ni Al 300 ℃ 3.5 11.2 18.9 1.4 4.8 27.5 350 ℃ 2.0 5.0 19.3 1.5 4.9 30.4 400 ℃ 1.5 4.2 19.6 1.5 4.9 30.3 500 ℃ 0.3 0.95 20.3 1.6 5.0 30.6

As shown in Table 2, as the roasting temperature is increased, carbon and sulfur components are gradually removed, whereas other valuable components tend to increase due to weight loss during roasting. Residual sulfur component was 5.0% and carbon component was 2.0% at low temperature roasting near 350 ℃.

(2) Experimental example of leaching ammonium sulfate of nickel component in low temperature roasting products

Since strong acid (HCl, H ₂ SO ₄ ) or strong alkali solution simultaneously dissolves various valuable metal elements contained in the low temperature roasted waste catalyst, it is difficult to produce high purity valuable metal compounds through a separation and purification process. Therefore, in the present invention, the leaching was carried out using an ammonium sulfate solution suitable for selectively leaching only the nickel component in the spent catalyst, and then the nickel in the leaching solution was separated and crystallized by a solvent extraction method to obtain nickel sulfate. At this time, the leaching tank was used as a pyrex reactor of 5l capacity with a device equipped with a stirring and temperature control device, the leaching agent concentration 400g / l, leaching time 1 hour and mineral solution concentration was fixed to 10%.

Table 3 below shows the effect of low temperature roasting temperature on the leaching rate when leaching the waste catalyst, which is roasted at low temperature under the same conditions as the above-mentioned device, with a nickel sulfate at a reaction temperature of 80 ° C. with ammonium sulfate solution.

Effect of Roasting Oxide Temperature on Leaching Rate of Nickel in Waste Catalyst at Low Temperature Roasting Roasting temperature (%) 300 350 400 450 500 Leaching rate (%) 40 80 48 20 17

As shown in Table 3, the leaching rate of nickel rapidly increases as the roasting temperature is increased from 300 ° C. to 350 ° C., and then rapidly decreases at a higher temperature, but the leaching rate is 80% at the roasting temperature of 350 ° C. Indicates the maximum value.

As described above, the nickel leaching rate reaches a maximum value at 350 ° C. and then rapidly decreases at a higher temperature because the nickel component is combined with alumina in the spent catalyst to generate an insoluble material of NiAl ₂ O ₄ .

Table 4 below shows the effect of the leaching temperature on the leaching rate when the nickel catalyst is leached from the waste catalyst calcined at 350 ° C. under the same conditions as those described above with ammonium sulfate solution.

Influence of Leaching Temperature of Nickel Components in Low Temperature Roast Product Leaching temperature (%) 20 40 60 80 90 Leaching rate (%) 20 45 62 80 79

As shown in Table 4, as the leaching temperature is increased, the leaching rate of nickel continues to increase, and the maximum value is shown at 80 ° C. The results of this leaching rate were not significantly different from the general leaching behavior according to leaching temperature.

Table 5 below shows the composition of the leaching solution obtained after leaching the nickel component in the waste catalyst roasted at low temperature under the above-described apparatus and conditions.

Change in composition according to acidity change of nickel leach solution (unit: ppm) Elemental component acidity (pH) Ni V Mo Fe Al 3.5 810 65 2.6 1.2 700 8.5 750 17 2.4 <1 5

As shown in Table 5, the pH of the leaching stock solution obtained after nickel leaching was 3.5, the content of nickel was 810 ppm, and the content of aluminum was 700 ppm. However, when ammonia water was added to the leachate to adjust the pH to 8.5 for solvent extraction, most of the aluminum components, which are problematic during solvent extraction, were removed in the form of precipitates (hydroxides), and the target nickel component forms a nickel ammonium complex. There was no change.

(3) Experimental Example of Manufacturing High Purity Nickel Sulfate by Solvent Extraction

Table 6 below shows the pH change of the solution when ammonia water was added to the nickel leachate to adjust the acidity (pH) of the leachate, and then the resulting impurity precipitate was removed. Shows the effect on the separation of nickel components. At the time of solvent extraction, the volume ratio (O / A) of the organic solvent and the aqueous solution was set to 1.

Effect of Acidity on Separation of Nickel during Solvent Extraction of Nickel Leaching Solution (Unit:%) Elemental component acidity (pH) Ni V Mo Al 7.5 25 61 0 One 8.5 66 37 One 2 9.5 92 5 2 3 10.5 71 0 3 4

As shown in Table 6, when the pH of the solvent extraction solution was 9.5, the extraction rate of the nickel component was the highest as well as the selectivity was the best. In addition, since the content of vanadium, molybdenum and aluminum components in the solvent extraction solution is very small compared to the nickel component, it is determined that high purity nickel compounds can be effectively obtained by performing the solvent extraction test steps of multi-step extraction, washing, back extraction and washing.

Using the above results, the bench-scale mixer-settler (composed of three stages of extraction, two stages of washing, two stages of back extraction, and one stage of washing) was separated and purified by a solvent extractor, and then back extracted with 1N H ₃ SO ₄ . The obtained concentrated nickel sulfate solution was crystallized to prepare a nickel sulfate compound (NiSO ₄ 7H ₂₀ ) of 99% or more.

Table 7 below shows the composition of the nickel sulfate solution obtained by separating and purifying the nickel component in the leaching solution by the above-described mixer-settler solvent extraction apparatus.

Chemical Composition of Nickel Sulfate Solution Obtained by Solvent Extraction Test of Leaching Solution ingredient Ni V Mo Al Content (ppm) 2,200 0.65 <0.1 2.1

As shown in Table 7, when the nickel sulfate solution obtained as a result of the solvent extraction test of the leaching solution is crystallized, more than 99% of the nickel sulfate compound (NiSO ₄ 7H ₂ O) containing a small amount of vanadium, molybdenum and aluminum components can be prepared. .

(4) Example of recovery of vanadium component from spent catalyst residue after nickel recovery

In the present invention, after the recovery of nickel, 4 equivalents of sodium carbonate is added to the spent catalyst residue and soda roasted at 900 ° C. for 2 hours, after which the soda roast product is leached at 80 ° C. under 10% mineral solution concentration for 1 hour, vanadium and The molybdenum component was leached about 88%. And after adjusting the acidity of the vanadium and molybdenum leaching solution to pH 8.0, by adding 3 equivalents of ammonium chloride to the leaching solution and reacted for 30 minutes, the vanadium component was obtained in the form of ammonium vanadate (NH ₄ VO ₃ ). The vanadium recovery in these experimental conditions was 98%. The ammonium vanadate precipitate thus obtained was dried and calcined to produce vanadium oxide (V ₂ O ₅ ) having a purity of 99% or more.

On the other hand, vanadium oxide obtained after roasting sodium carbonate immediately under the same experimental conditions without low-temperature oxidation was contained a considerable amount of impurities, which was less than 99% pure. In other words, it can be seen that the vanadium purity recovered from the spent catalyst residue obtained by recovering the nickel component by low temperature oxidation is higher than the purity of the vanadium recovered by roasting directly with sodium carbonate without low temperature oxidation.

(5) Example of recovery of molybdenum component from filtrate after vanadium recovery

In the present invention, after adjusting the acidity of the filtrate after recovery of vanadium to pH 6.0, 30 equivalents of calcium chloride is added to the filtrate for 30 minutes, the molybdenum component in the form of calcium molybdate (CaMoO ₄ ) under the conditions of recovery of 80% Could get When the calcium molybdate precipitate thus obtained was dried, calcium molybdate having a grade of about 95% was produced. In addition, when comparing the quality of CaMoO ₄ obtained by roasting petroleum desulfurization waste catalyst with low temperature oxidation and immediately roasting sodium carbonate without low temperature oxidation, calcium molybdate obtained after roasting sodium carbonate immediately without low temperature oxidation It contained a large amount of calcium sulfate (CaSO ₄ ) impurity and less than 80%.

The reason for the low quality of calcium molybdate in the absence of low temperature oxidation is that the sulfur component in the waste catalyst is not sufficiently removed, so it exists in the form of SO ₄ ^-2 ions in the leachate, and calcium chloride is added to form calcium molybdate precipitate. Calcium sulphate is coprecipitated and contained in calcium molybdate precipitate.

That is, when molybdenum component is recovered with the leaching solution obtained after roasting the waste catalyst at low temperature oxidation and sodium carbonate, it is considered to be an effective method because calcium molybdate is higher in quality than the case where no low temperature oxidation is performed.

As described above, the present invention separates and recovers the nickel component in the form of NiSO ₄ for plating in a solution of petroleum desulfurization waste catalyst (VRDS) at low temperature of roasted oxide and ammonium sulfate, and recovers the spent catalyst residue from which the nickel component is recovered. Soda roasting, water leaching and precipitation can effectively separate and recover as V ₂ O ₅ and CaMoO ₄ forms for alloy addition.

This method of the present invention not only continuously separates and recovers the nickel, vanadium and molybdenum components contained in the spent catalyst, but also the purity of the obtained V ₂ O ₅ and CaMoO ₄ compounds prepared by a conventional simple soda roasting process. It has several advantages that result in much better results than compounds.

Claims (4)

In separating and recovering nickel, vanadium and molybdenum from petroleum desulfurization waste catalyst, The nickel component of the valuable metal contained in the petroleum desulfurization waste catalyst is separated and recovered in the form of NiSO ₄ through roasting, ammonium sulfate leaching, solvent extraction, and crystallization, and vanadium and molybdenum contained in the spent catalyst residue after nickel recovery. A method for separating and recovering nickel, vanadium and molybdenum from a petroleum desulfurization waste catalyst, characterized in that the components are separated and recovered in the form of V ₂ O ₅ and CaMoO ₄ through high temperature soda roasting, water leaching, selective precipitation and calcination. The method of claim 1, The low temperature oxidation of the petroleum desulfurization waste catalyst is 340 ° C. to 360 ° C., and the time is 1 hour. The leaching temperature is 80 ° C., the leaching time is 1 hour, and the leach concentration is 1 hour. Separation and recovery method of nickel, vanadium and molybdenum from petroleum desulfurization waste catalyst, characterized in that 400g / l. The method of claim 1, In the solvent extraction process, the acidity of the ammonium sulfate leaching solution was adjusted to pH 9.5, and the nickel component was selectively extracted from a mixer-settler solvent extractor using a 10% LIX 84 solvent extractant, and then reversed into a 1N H ₂ SO ₄ solution. Separation and recovery of nickel, vanadium and molybdenum from petroleum desulfurization waste catalyst, characterized in that the recovery is carried out with nickel sulfate by extraction. The method of claim 1, The residue of the petroleum desulfurization waste catalyst obtained after the nickel recovery was separated into vanadium by addition of 3 equivalents of ammonium chloride in a 900 ° C. high temperature soda roast, 80 ° C. water leach, and a water leach solution. A method for separating and recovering nickel, vanadium and molybdenum from a petroleum desulfurization waste catalyst, characterized in that the molybdenum is separated and recovered by adding an equivalent amount of calcium chloride.